function preload(imagesrc)
{
    preloaded_image = new Image();
    preloaded_image.src = imagesrc;
/*    preloaded_image.onload=function(){alert('image ' + imagesrc + ' preloaded')}; */
//     preloaded_image.onload=function(){document.getElementById('photo').onlclick = document.location = imagesrc }

}